Mysqlconnection Problems with concurrent connections

Recently in the process of doing a project encountered a MySQL in the concurrency initialization problem, the scenario is this:

I set up multiple actions at the same point in the job to access the database update data, and the result throws the following question when creating the connection:

Note that and a DataReader is open, and the Connection is with use exclusively by. DataReader. You cannot execute any commands for the Connection, including creating another DataReader, until the original DataReader I S closed.

The code I created for the link is as follows:

public class DBConnection    {        private static mysqlconnection _conn;        public static mysqlconnection Conn        {            get            {                if (_conn = = null)                {                    Mysqlconnection connection = New Mysqlconnection (constvalue.dbconnectionstring);                    _conn = connection;                }                return _conn;            }        }                public static Mysqlconnection CreateConnection ()        {            return Conn;        }    }

Before using the SQL Server database connection did not have any problems, and later find the data found this is a MySQL connection bug.

The official website is described as follows: https://bugs.mysql.com/bug.php?id=7248

MySql.Data.MySqlClient.MySqlException:There is already a open DataReader associated with this Connection which must be C losed first.

That is, only one connection is allowed to be opened to read data at the same time.

The analysis on the StackOverflow is as follows:

You is using the same connection for the and the DataReader ExecuteNonQuery . This isn't supported, according to MSDN:

Note that and a DataReader is open, and the Connection is with use exclusively by. DataReader. You cannot execute any commands for the Connection, including creating another DataReader, until the original DataReader I S closed.

This will make it clear that we must create a connection object each time when we are creating the connection. Change the code:

public class DBConnection    {public        static mysqlconnection Conn        {            get            {                mysqlconnection Connection = new Mysqlconnection (constvalue.dbconnectionstring);                return connection;            }        }        public static Mysqlconnection CreateConnection ()        {            return Conn;        }    }

This solves the problem of concurrent access.

Stepping on the pit, the record is to grow.

Mysqlconnection Problems with concurrent connections